To meet the demand for wireless data traffic, which has increased since deployment of 4th-generation (4G) communication systems, efforts have been made to develop an improved 5th-generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post long-term evolution (LTE) system’.
It is considered that the 5G communication system will be implemented in millimeter wave (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To reduce propagation loss of radio waves and increase a transmission distance, a beam forming technique, a massive multiple-input multiple-output (MIMO) technique, a full dimensional MIMO (FD-MIMO) technique, an array antenna technique, an analog beam forming technique, and a large scale antenna technique are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a device-to-device (D2D) communication, a wireless backhaul, a moving network, a cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, and the like.
In the 5G system, a hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and a sliding window superposition coding (SWSC) as an advanced coding modulation (ACM) scheme, and a filter bank multi carrier (FBMC) scheme, a non-orthogonal multiple Access (NOMA) scheme, and a sparse code multiple access (SCMA) scheme as an advanced access technology have been developed.
Recently, data traffic has increased drastically due to the dissemination of smart phones. The number of smart phone users increases, and application services using the smart phones, such as a social networking service (SNS), games, and the like are more popularized, so the data traffic is expected to increase much more than now.
In particular, if even intelligent machine-to-machine (M2M) communication utilizing things, such as communication between people and things, communication between things, and the like, which is expected to provide a new mobile market, is popularized in addition to the communication between people, the traffic transmitted to a base station (BS) or an evolved node B (eNB) is expected to increase dramatically, so it may be difficult to deal with the traffic.
As technology capable of addressing these issues, a direct communication technology between devices has attracted great attention. This technology, which will be referred to D2D communication, has attracted great attention for all of a licensed band in a mobile communication system and an unlicensed band such as a wireless local area network (WLAN).
A D2D communication technology which is based on an LTE scheme of the 3rd generation partnership project (3GPP) may be classified into a D2D discovery procedure and a D2D communication procedure.
The D2D discovery procedure denotes a procedure in which one device identifies identities or interests of other devices which are proximate to the device, or informs an identity or an interest of the device to the other devices which are proximate to the device. Here, an identity or an interest may be an identifier (ID) of a device, an application ID, a service ID, or/and the like, and may be implemented with various forms according to a D2D service and operating scenario.
A D2D discovery procedure which has been studied in a technology of the related art is based on an environment in which a serving cell of a device is configured with a single frequency. Further, a D2D transmitting procedure which is supported in a technology of the related art has been performed only at a serving carrier as a frequency which is used by a serving cell.
So, there is a need for an operation and a procedure for transmitting a D2D discovery signal through a non-serving carrier as a frequency which is not used in a serving cell.
An LTE mobile communication system may support a carrier aggregation (CA) scheme for increasing efficiency of a cellular frequency resource and a data rate. In the CA scheme, a serving cell may be configured with a multi-carrier, and may perform a receiving operation and a transmitting operation on different frequencies at the same time.
So, there is a need for an operation and a procedure for applying a CA scheme in a D2D communication system which is based on a cellular scheme.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.